There is known, as an output control for an internal combustion engine, a torque demand control for controlling an output torque of the internal combustion engine by calculating a target output torque of the internal combustion engine based on a driver's manipulation amount of an accelerator pedal and adjusting an intake air amount based on the target output torque.
For example, a control device disclosed in Patent Document 1 calculates a target drive shaft torque based on an accelerator manipulation amount and a vehicle speed, divides the target drive shaft torque by a final gear ratio, and calculates a target output shaft torque of a transmission. Furthermore, the control device divides the target output shaft torque by a torque doubling ratio set in the transmission and a torque converter to thereby calculate a target output torque of the internal combustion engine, and sets an opening degree of a throttle valve based on the target output torque and the rotational speed of the internal combustion engine.
As described in Patent Document 1, when the target output torque of the internal combustion engine is calculated in light of torque conversion in the transmission, the target output torque can be calculated to correspond to a transmission gear ratio of the transmission, that is, (rotational speed of an input shaft)/(rotational speed of an output shaft) of the transmission.    Patent Document 1: Japanese Laid-Open Publication No. 8-218919